کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
187418 | 459643 | 2013 | 10 صفحه PDF | دانلود رایگان |

Electroreductive desorption of a highly ordered self-assembled monolayer (SAM) formed by the araliphatic thiol (4-(4-(4-pyridyl)phenyl)phenyl)methanethiol leads to a concurrent rapid hydrogen evolution reaction (HER). The desorption process and resulting interfacial structure were investigated by voltammetric techniques, in situ spectroscopic ellipsometry, and in situ vibrational sum-frequency-generation (SFG) spectroscopy. Voltammetric experiments on SAM-modified electrodes exhibit extraordinarily high peak currents, which differ between Au(1 1 1) and polycrystalline Au substrates. Association of reductive desorption with HER is shown to be the origin of the observed excess cathodic charges. The studied SAM preserves its two-dimensional order near Au surface throughout a fast voltammetric scan even when the vertex potential is set several hundred millivolt beyond the desorption potential. A model is developed for the explanation of the observed rapid HER involving ordering and pre-orientation of water present in the nanometer-sized reaction volume between desorbed SAM and the Au electrode, by the structurally extremely stable monolayer, leading to the observed catalysis of the HER.
Figure optionsDownload as PowerPoint slideHighlights
► Araliphatic SAM with extraordinary electrochemical stability.
► Enhancement of the hydrogen evolution after reductive SAM desorption.
► In situ real time sum frequency generation (SFG) spectroscopy.
► Relation between reductive SAM desorption and hydrogen evolution.
Journal: Electrochimica Acta - Volume 90, 15 February 2013, Pages 17–26